"Yo no le respondí."
Translation:I didn't answer him.
"I didn't respond to him" should also be accepted. Reported June 2018.
Why would we use the indirect object pronoun "le" here as opposed to just "lo"?
'lo' is the direct object where as 'le' is the indirect object. In this sentence 'I' is the subject (doing the action) and 'him' is the indirect object (who is being acted upon).
You are correct that "him" is the indirect object. However, "I" is the subject. There is no direct object in this sentence, but it's sort of implied in the verb itself. For instance, you can read a book or drive a car. "Book" and "car" are direct objects. But how can you "answer" (or not, in this case) a person? You "answer" someone with the thing you're saying:
I answered (something to) him.
I didn't answer (anything to) him.
I'm sure there's a term for this kind of verb that someone way smarter than I am would know. Apologies if this explanation is confusing.
lol... not confusing at all. I didn't event realize I mixed the subject and direct object up. Guess I still have a way to go figuring out the parts of speech. Very good explanation by the way.
"I did not respond to him" was incorrect. I think it should have been accepted.
I didn't answer .. infers him , .. my conversation need is never sufficient to comply with these grammatical niceties!! Who speaks perfectly correct english these days!!??